The present invention relates to a device for aligning and feeding an original from a feed table to an object stage of a copier, and more specifically to such a device having a drivable feed roller which is located in one corner of the feed table obliquely to the direction of transport of the original, and sensors for scanning the original in various positions and for triggering a transport movement of the original. One of these sensors briefly drives the feed roller via a control system when it detects the presence of an original. The device also has a registering straight-edge which can be moved out of the transport path of the original.
A device of this type for aligning and feeding originals in a copier has been disclosed by German Offenlegungsschrift No. 2,712,143, by means of which two originals, which are aligned side by side next to each other, can be fed from a feed station to the object stage with the scanning station of a copier, the two originals individually being laid down one after the other onto the feed station by the operator.
Semi-automatic feeding of individual originals is described in U.S. Pat. No. 3,908,986. In semi-automatic feeding of originals, the originals are manually laid down onto a feed station, and only the feeding to the object stage takes place automatically, in contrast to completely automatic feeding of originals, in which a stack of originals or artwork is laid down into a supply compartment and then the stacked originals are individually conveyed one after the other by machine from the stack to the feed station and from there to the object stage. In the known semi-automatic feeding device, the individual originals, which are laid down individually onto the feed station, are gripped by an aligning device, are aligned and, as the result of control actions by the machine, are gripped by the transport device and pushed forward onto the object stage for copying or scanning.
In the known semi-automatic feeding devices, as in the devices according to U.S. Pat. No. 4,023,791, German Offenlegungsschrift No. 2,758,044 and German Auslegeschrift No. 2,438,483, the transport devices consist of transport belts and transport rollers. In these devices, due to differences in friction and due to fluctuations in the layer thicknesses or in the diameter of the transport rollers, offsets of the original occur time and again during the movement over the object stage. Due to this incorrect or non-aligned positioning of the original on the object stage, copies are then obtained in which the image is laterally offset at an angle relative to the edges, and the copies therefore cannot be used.
German Offenlegungsschrift No. 2,610,480 discloses a sheet-feeding device for a facsimile system or a similar system, which has a suction device with a suction pad which is brought into contact with the stack of sheets. A contact pressure part is carried by the suction pad and surrounds the latter, one end of the contact pressure part projecting beyond one end of the suction pad. In this sheet-feeding device, air is blown against the edges of the sheets in the stack and a suction force is exerted via the suction pad, or via several suction pads, in order to pick up the top sheet of the stack in this way. There is no aligning and positioning of the sheet during pick-up, or during laying-down after the transport step.